Section on Directed Gene Transfer, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892; email:
Annu Rev Virol. 2015 Nov;2(1):119-34. doi: 10.1146/annurev-virology-100114-055056.
A retroviral etiology for malignant neoplasias in koalas has long been suspected. Evidence for retroviral involvement was bolstered in 2000 by the isolation of a koala retrovirus (KoRV), now termed KoRV-A. KoRV-A is an endogenous retrovirus-a retrovirus that infects germ cells-a feature that makes it a permanent resident of the koala genome. KoRV-A lacks the genetic diversity of an exogenous retrovirus, a quality associated with the ability of a retrovirus to cause neoplasias. In 2013, a second KoRV isolate, KoRV-B, was obtained from koalas with lymphomas in the Los Angeles Zoo. Unlike KoRV-A, which is present in the genomes of all koalas in the United States, KoRV-B is restricted in its distribution and is associated with host pathology (neoplastic disease). Here, our current understanding of the evolution of endogenous and exogenous KoRVs, and the relationship between them, is reviewed to build a perspective on the future impact of these viruses on koala sustainability.
考拉恶性肿瘤的逆转录病毒病因由来已久。2000 年，考拉逆转录病毒（KoRV）的分离为逆转录病毒的参与提供了证据，现在称为 KoRV-A。KoRV-A 是一种内源性逆转录病毒，即感染生殖细胞的逆转录病毒——这一特征使其成为考拉基因组的永久居民。KoRV-A 缺乏外源性逆转录病毒的遗传多样性，而这种遗传多样性与逆转录病毒引起肿瘤的能力有关。2013 年，在洛杉矶动物园患有淋巴瘤的考拉中获得了第二种 KoRV 分离株 KoRV-B。与存在于美国所有考拉基因组中的 KoRV-A 不同，KoRV-B 的分布受到限制，并且与宿主病理学（肿瘤疾病）相关。在这里，我们回顾了对内源性和外源性 KoRV 的进化及其之间关系的现有理解，以建立对这些病毒对考拉可持续性未来影响的观点。
